1. Field of the Invention
The present invention relates to an apparatus for manufacturing a ceramic green sheet which is employed for a laminated ceramic electronic component.
2. Description of the Background Art
A laminated ceramic electronic component such as a laminated ceramic capacitor, a laminated inductor or a multilayer circuit board, for example, is obtained by stacking ceramic green sheets. A laminated ceramic capacitor, which is the most typical example of such a laminated ceramic electronic component, has generally been manufactured in the following manner:
(1) A mother sheet of green ceramic is punched into a rectangular form, to obtain a ceramic green sheet for stacking. PA1 (2) Internal electrodes are printed on the rectangular ceramic green sheet. PA1 (3) The printed internal electrodes are dried. PA1 (4) A plurality of such ceramic green sheets, which are provided with internal electrodes of a first pattern, are alternately stacked with those provided with internal electrodes of a second pattern, which is different from the first pattern. PA1 (5) The stacked green sheets are aligned on the basis of their outlines. PA1 (6) The formed laminate of the ceramic green sheets is introduced into a die assembly and pressurized. PA1 (7) The laminate is cut into chips for forming independent laminated ceramic capacitors. Then steps of firing the chips and forming external electrodes thereon are carried out to obtain a desired laminated ceramic capacitor.
In the aforementioned method of manufacturing a laminated ceramic capacitor, the internal electrodes are printed in the step (2) after the rectangular ceramic green sheet is obtained in the step (1). If misregistration occurs in the step of printing the internal electrodes, therefore, such misregistration of the internal electrodes with respect to the outsides of the chips will be carried over to the final product, since such ceramic green sheets are stacked on their basis of the outlines in the step (5). Thus, the laminated ceramic capacitors formed in this way are prone to have variations or statistical dispersion in their capacitance.
In the step (5), the stacked ceramic green sheets are registered by means of vibration or another known method so that the outlines thereof are aligned with each other. However, it is impossible to improve stacking accuracy since the ceramic green sheets are relatively inferior in mechanical strength. This also leads to dispersion of the acquired capacitances of the final chips, particularly in laminated ceramic capacitors.
Further, the capacitance acquired by each laminated ceramic capacitor is substantially determined at the step (2). In the step (2), the internal electrodes are printed on the ceramic green sheet which has already been punched into a rectangular outline, and such ceramic green sheets are aligned in the stacked state on the basis of the outlines in the step (5). Thus, it is impossible to arbitrarily change the capacitance acquired by the formed laminated ceramic capacitor, since the ceramic green sheets are provided with internal electrodes having the same types of patterns. In order to obtain a plurality of types of laminated ceramic capacitors having different capacitances, it is necessary to prepare a plurality of types of ceramic green sheets having different patterns of internal electrodes in the step (2).
While it is necessary to directly handle the ceramic green sheet in the steps (2) to (5), the difficulty of such handling is increased as the thickness of the ceramic green sheet is reduced.